Halofantrine 250mgs/tablet. 2 tablets in one dose,then 2 tabs after 6. of convulsions,epilepsy in first. Phenytoin,carbamazepine and.Martindale: The Complete Drug Reference Ondansetron and other 5-HT 3 antagonists may cause headache, a sensation of flushing or warmth, hiccups, and constipation.